The present invention relates to a telescopic rod, and more particularly to a telescopic rod with good locking effect.
FIGS. 7 to 9 show an existing telescopic rod 8 including an outer tube 81. One end of the outer tube 81 is formed with a rectangular through hole 811. A C-shaped collar 82 is fitted in the outer tube 81. The collar 82 has a flange 821 at one end. The collar 82 serves to protect an inner tube 83 from being scraped by the outer tube 81. In addition, a latch lock 84 is fitted around the outer tube 81. A pressing lever 85 is pivotally disposed on one side of the latch lock 84 for pressing a pressing block 86 positioned in the through hole 811. The telescopic rod 8 is connected with an appliance (such as a microphone) for increasing length. Also, it is often necessary to rotate the telescopic rod by a certain angle to meet the using angle of a user. Therefore, the outer tube 81 or inner tube 83 is necessary to be rotated through a certain angle. This will make the collar 82 biased to one side. Under such circumstance, the pressing block 86 will press the collar 82 and fail to totally abut against the inner tube 83. Accordingly, the inner tube 83 may slip relative to the outer tube 81 and the latch lock 84 will lose its function.
FIGS. 10 and 11 show another type of telescopic rod 9 in which the walls of the outer and inner tubes 91, 92 are pressed with two guide channels 93, whereby the outer and inner tubes 91, 92 are prevented from rotating relative to each other. The collar 94 is formed with a bent section 941 on one side in accordance with the guide channels 93, whereby the collar 94 will not be rotated. The pressing block 95 has a projecting section 951 in accordance with the guide channels 93 for enhancing tightness. However, in manufacturing, such telescopic rod 9 still has the following shortcomings:
The outer and inner tubes 91, 92 must be pressed with the guide channels 93. Due to limitation of manufacturing technique and cost, the cost for the mold will be relatively high in the case that steel tube (or iron tube) with higher hardness is used as the material. Therefore, softer aluminum tube is selectively used as the material for reducing the cost. However, when suffering heavy load, the aluminum tends to be bent. In addition, after pressed by the pressing block 95, the aluminum tube is subject to deformation. This will make the pressing block unable to tightly clamp the inner tube.